Powder mixtures having binders are used in forming articles of various shapes. For example ceramic or metal powder mixtures having cellulose ether binders, are formed into honeycombs which are used as substrates in catalytic and adsorption applications. The mixtures must be well blended and homogeneous in order for the resulting shaped body to have good integrity in size and shape and uniform physical properties.
Rapid-setting characteristics are especially important for honeycomb substrates. If the cell walls of the honeycomb can be solidified quickly after forming, the dimension of the greenware will not be altered in subsequent cutting and handling steps. This is especially true for a fragile thin-walled or complex shaped product, or a product having a large frontal area.
Various techniques have been disclosed for rapid stiffening of such batches, such as adding various rapid setting additives e.g. surfactants, binders and water soluble polymers as disclosed in U.S. Pat. No. 5,258,205.
There still remains a need to further improve the setting up characteristics of formable mixtures.
The present invention fills this need.